<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>bootstrap</title>
    <link rel="stylesheet" href="css/bootstrap.min.css">
    
</head>
<body>
<div class="btn-group ">
  <button class="btn btn-default">1111</button>
  <button class="btn btn-default">2222</button>
  <div class="btn-group">
    <button class="btn btn-default dropdown-toggle"  data-toggle="dropdown">
      3333
      <span class="caret"></span>
    </button>
    <ul class="dropdown-menu">
      <li>1</li>
      <li>2</li>
      <li>3</li>
    </ul>
  </div>
</div>



<div class="btn-group-vertical ">
  <button class="btn btn-default">1111</button>
  <button class="btn btn-default">2222</button>
  <div class="btn-group">
    <button class="btn btn-default dropdown-toggle"  data-toggle="dropdown">
      3333
      <span class="caret"></span>
    </button>
    <ul class="dropdown-menu">
      <li>1</li>
      <li>2</li>
      <li>3</li>
    </ul>
  </div>
</div>

<br/>

<div class="btn-group btn-group-justified">
  <div class="btn-group">
    <button class="btn btn-info">按钮1</button>
  </div>
  <div class="btn-group">
    <button class="btn btn-info">按钮2</button>
  </div>
  <div class="btn-group">
    <button class="btn btn-info">按钮3</button>
  </div>
  <div class="btn-group">
    <button class="btn btn-info">按钮4</button>
  </div>
</div>

<br/>

<div class="btn-group btn-group-justified">
  <a class="btn btn-info">按钮1</a>
  <a class="btn btn-info">按钮2</a>
  <a class="btn btn-info">按钮3</a>
</div>

<br/>
<div class="btn-group">
  <button class="btn btn-default dropdown-toggle" data-toggle="dropdown">
    Action
    <span class="caret"></span>
  </button>
  <ul class="dropdown-menu">
    <li><a href="">Action</a></li>
    <li><a href="">Action</a></li>
    <li><a href="">Action</a></li>
    <li role="separator" class="divider"></li>
    <li><a href="">Action</a></li>
  </ul>
</div>


<div class="btn-group dropup">
  <button class="btn btn-danger btn-lg">按钮</button>
  <button class="btn btn-danger dropdown-toggle btn-lg" data-toggle="dropdown">
    <span class="caret"></span>
  </button>
  <ul class="dropdown-menu">
    <li>1</li>
    <li>2</li>
    <li>3</li>
  </ul>
</div>
<script src="js/jquery-3.6.0.min.js"></script>
<script src="js/bootstrap.min.js"></script>
</body>
</html>